Past repair projects include parking structure design and repair, forensic engineering and expert testimony, facade defects, roof replacement, masonry repairs, mold source detection, soil settlement, retaining walls, and foundations.

For details on Construction Management  & Code Consulting please visit  BlueHorseshoeAdvisors.com.

Facades

Sounding and locating spalling concrete on a Manhattan high rise.

Part of our inspection and repair procedure is to ride the swing stage scaffolding and locate areas of concrete and masonry that has become stressed due to original construction defects, original design defects or corrosion.  Below are three photographs of Eric W. Cowley, PE performing an inspection of a high rise onManhattan’s upper east side, the associated concrete defect located at one location and the outriggers used for the swing stage scaffolding.

E58ST Cowley 1 slab edge broken

Outriggers used for the swing stage scaffolding.

Outriggers used for the swing stage scaffolding.

Exposed Slab Edges

MANHATTAN (Deteriorated Slab Edges & Spalls)

This past summer, we provided consultation for the repairs to the exposed slab edges and masonry of (2) structures: a 32 story condominium and a 22 story condominium. We were initially contacted because concrete was spalling (flaking off) and chunks were falling from the buildings.

Deteriorated Slab Edges
Concrete ‘spalls’ are sectional pieces of concrete that flake away from the base material and are due to the increase in stress in the concrete as a result of the volume change that occurs when reinforcing steel corrodes. Measures to limit corrosion are normally taken at the time of construction by doing a couple of things:

• Most importantly ‘maintaining cover’. ‘Cover’ refers to a sufficient amount of concrete between the steel reinforcement and the nearest exposed surface. Cover is specified by the ACI Code. In this case, sufficient cover should have been 1 1/2″. For many of the defect areas examined, the existing cover was less than 1/2″.

• Using ‘air entrained’ concrete. For concrete that is to be exposed to the weather, air entrainment is an additive that effectively reduces the pore size of the concrete and inhibits moisture propagation.

When these buildings were constructed, there was a breakdown in quality control during the setting of the forms and the placement of the reinforcement. It would have been obvious to either the form setters or the reinforcing steel installers that appropriate cover was not being achieved. The overall consistency of this problem indicates that little or nothing was done to correct the problem during construction.

It was interesting to note that some of the spalls are themselves patches. That is to say, someone identified this problem in the past, and attempted to add cover, or patch over the exposed bars.
On occasion, when forms are removed, honeycombing exists (where the concrete was not sufficiently consolidated in a tight space) and bars remain exposed. It is customary to immediately patch these unsightly areas in the hopes of marrying the patch mix with the fresh concrete and eliminate variation in color or shade.

Newly installed masonry undergoes volume changes due to moisture absorption for the first 7 or 8 years of its installed life. After this time, masonry expansion due to moisture stabilizes, however volume changes, although of significantly less scale, continue to occur due to thermal effects.
Volume changes are accommodated during the design of structures by means of ‘soft’ joints (gaps allowing movement) at the underside of each eyebrow. At locations where soft joints were not properly installed, or where the subsequent volume change of the masonry completely utilizes the gap, the masonry becomes muscle bound. This muscle bound condition creates stress concentrations in the veneer masonry causing bulging and fracturing.

Calcium carbonate stains, characterized by hardened, encrusted white masses, are the result of carbon hydroxide, (which is present in the mortar), being brought to the surface through moisture migration where it reacts with carbon dioxide and is left to form calcium carbonate. This material (aka limestone) is the same material that forms stalactites in caves. It is very hard and almost impossible to clean off of masonry surfaces. To create this condition, there must be an excessive source of moisture present in the masonry assembly. The entrapped water prolongs the curing process of the mortar and produces excessive lime.

The cause of these stains can usually be traced back to faulty design and construction practice. Regardless of impurities in the mortar or the masonry itself, excessive amounts of calcium carbonate will not be created if proper precautions and high quality workmanship are employed.

Some of the more common shortcomings are:

• failure to protect masonry supplies during construction,
• failure to cover and protect unfinished walls during construction,
• inadequately flashed copings and parapet walls,
• the absence of drips on copings, cornices or projecting members,
• poorly filled mortar joints,
• the absence of damp-proofed courses at the ground level,
• failure to patch or repair opened mortar joints,
• the use of dense mortar or masonry units which absorb water through cracks then are slow to dry out.

In many cases, the repair procedure for concrete spalls and occasional exposed reinforcement is to simply cut and remove the bar. However, the development length for the reinforcing is a function of the concrete cover. In other words, the bar end that you don’t see (because it’s buried inside the slab) is relying on the hooked end you do see to ‘grab’ concrete and function as designed.

Therefore, we always attempt to leave the bar and make a repair.

At each spall location the repair, involves:

• square cutting around the spall to a depth adequate for the patch to get a ‘bite’;
• mechanically and hand wire brush the exposed corroded bar to a brite condition;
• the application of a zinc based coating to the bar;
• patch installation;
• and finally, some color blending so the eyebrow has a uniform appearance.

Where broken or bulged masonry has occurred, the units must be cut out and replaced. The reason for stress must also be determined since masonry doesn’t crack or move on its own. If the source of the cracking and bulging is due to seized soft joints, the masonry below the joint must be removed and cut down in size. If the broken masonry is due to other factors such as lack of vertical soft joints, (expansion control), deflections, soaps, etc. then other remedies will be employed. Caulk joints that have bulged are also a sign of excess compression.
Calcium carbonate stains can be removed by the use of acid, a wire brush and lots of labor. The bigger issue is to resolve the saturation of the mortar due to moisture infiltration. This usually involves considerable masonry and flashing reconstruction.

Long Term Effects

• The threat from the spalls is falling debris. This is obviously a threat to the public.
• The threat from broken masonry and compressed joints is the stressed masonry. Sectional pieces of masonry, stressed under compression, shear off in 1/2″ thick lenses. This is obviously a threat to the public.
• The constant saturation that occurs, in order to create calcium carbonate, erodes both the mortar and the masonry. Since mortar is 12% to 20% calcium hydroxide after the curing reaction, the continual saturation removes the lime from the mortar and over cures the mortar. What remains is mortar that is very hard, very brittle and shrinks and debonds from the masonry. This debonding causes more moisture to enter the void, furthering the process.

We addressed all of these problems by:

• Creating elevation drawings of the structures;
• On these elevation drawings the areas requiring repair, as well as corrective details, were indicated;
• All defect areas were quantified and a budget number for the corrective work was generated and broken down into hazardous (required work), additional recommended work, and other work to be added at the Owner’s option;
• Specifications were created that defined the parameters of the work, the rules of the building and the materials to be used;
• Unit prices for the work were established and were applied to the estimated quantities;
• The plans were filed with the NYCDOB and sent out for bidding.

Given the time delay in the preparation of Bid documents and for the bidding process, the Owners contracted to have hazardous material ready to fall from the building removed under controlled conditions. To do this, sidewalk protection was installed, the building was rigged, and a contractor set out to knock loose and collect any material that may fall in the interim. After the conditions were stabilized, the sidewalk protection was removed until the construction documents were created, the funds were allocated, and the repair work was set to begin. At that point, the sidewalk protection was reinstalled and the repairs were conducted, until the building was sound.

Park Avenue, Manhattan (Loose Granite Panels)

Recently, we were hired as consultants to another NYC engineering firm regarding water infiltration occurring through the facade of a 30+ story granite cladded structure in Manhattan. The water infiltration, it was readily seen, was caused by the loosening and misalignment of the granite stone cladding, which caused the sealant between the panels to separate. After identifying the problem, our job was to identify the cause of the misalignment, and recommend measures for correction.

The Cause
The original fastening detail of the granite panels incorporated a glued liner plate fastened to the back of the granite panel. This liner plate was set on an inverted angle that was fastened to the frame. This liner panel is the sole means of support for the granite panel. Additionally, there are wires embedded into the panel edge at the sides, near the top, that prevent the outward movement of the panel.

The original detail, using the glued liner plates, is a questionable means of sole structural support for the sizable granite units. In addition to this, the casting of an irregular spandrel, causes the stone setters to excessively shim the units to maintain a straight line and, subsequently, lose the intended bearing area.

The torn and compressed sealant as well as the cracked stone edges indicated that the stone cladding panels had undergone differential movement compared with the structural frame. Since the stone cladding is the more rigid system, as compared to the building frame, the cladding must be allowed to move independently of the frame yet remain structurally sound. This movement may be caused by many factors: the time dependent frame shortening of the structure, wind loads and natural thermal and moisture effects.

Frame shortening of the structure refers to the shrinkage of the frame over time due to constant loading and the initial natural shrinkage of new concrete. This shortening of the building frame must be accommodated by the joints between the stone panels.
Wind loading causes deflections in the frame that must also be accommodated by the joints between the stone panels.
Thermal and moisture effects, causing movement, must also be accommodated. These effects are greater at the parapet, given the parapets exposure to the elements on (2) sides.

Recommendation
The epoxy liner that provides support and the lack of adequate bearing observed at the failed panel (and the one directly above) is an unacceptable and unstable condition (see the sketch). It is reasonable to assume that this condition exists at numerous locations throughout the structure.

A pin system, to attach the panels to the backup, may not be feasible since pins are not adequately capable of transferring lateral loads, nor can their embedment be properly confirmed.

We provided a detail calling for edge support of each panel with some panel modifications required.
As far as the scope of the work, we recommended that the parapet, with its numerous loose and displaced stones, be completely skinned, proper anchorages installed, the panels modified, and then reinstalled. We also recommended that the condition of the remaining facade be assessed and a repair scheme devised to address any loose and displaced stones discovered.

Frame Shortening

MID-TOWN, MANHATTAN (Masonry Fracture Caused by Frame Shortening)

Late in the summer, we were contacted by the managing agent of a luxury mid-town high rise. At issue: a maintenance worker happened to look out a window and noticed a severe masonry fracture and a section of brick about 15 sf in area, ready to plumment 17 floors to the street.Sidewalk protection was ordered below the affected area and was set up immediately. A contractor, with whom we have worked in the past, set up a scaffold on the suspect line and I prepared for a ‘drop’. A drop is an industry term for riding a scaffold from the top of a building, to the street. In this case, 50+ stories. Riding the rig to the affected area revealed the cracked masonry. (See the photo at the right). The masonry is veneer brick, and on this line, encases a concrete column. The masonry is attached to the column with metal straps set between the masonry units. These straps are attached to the column by means of dovetail slots…metal channels set into the concrete when its placed (if you’re lucky). All of the concrete slab edges (aka eyebrows…see other articles this issue) were covered with metal cladding sometime in the past. Whenever metal cladding is applied to masonry or concrete it tends to smack of one thing…cheap. In my experience, metal cladding has been applied to slab edges, parapet tops, terrace edges, etc. usually (is 9 out of 10 usually enough) to cover a defect, with the hope everyone forgets about it. Unfortunately, for the initiators, the plan backfires, and, equally unfortunately, memories are still quite fresh (although the versions are different).

But I digress.

Why did this crack happen? Very simple. Masonry expands and concrete buildings shrink. This differential movement must be accomodated were the two meet…any questions? Here’s the kicker. The stacked masonry at this location exerted enough stress onto the exposed slab edge that it actually sheared it off. (Both photos below are of the same location..just opposite hand). The sheared section of concrete (which weighed about 40 lbs) was held in place by two sheet metal screws and about six lineal feet of caulk.We ordered the immediate removal of the cracked masonry and the sheared concrete. We also inspected the remainder of the ‘drop’ and identified additional defect areas for repair.

 

While the managing agent and the Board of Directors were pondering my recommendations and fee proposal (to examine the rest of the structure), I issued a repair sketch (partial sketch shown below) to render a repair to the sheared slab edge. The contractor issued a material data sheet on the brick he wanted to use for the repair for my review. This data sheet, and those like it, are important. It gave me the physical characteristics of the masonry to be used.Such things as density, moisture absorption rates and thermal reactivity are important to the Engineer in determining the suitability of the selected masonry for repair. This information also gives the Engineer the data he needs to calculate the size of the required ‘soft’ joint. By calculating the expansive characteristics of the masonry, and by calculating the ‘creep’ or shortening of the building frame, we can determine the size of the void necessary at every rigid location. In this case, at the underside of every exposed slab edge.

 

When performing maintenance on your property, be mindful of the tendency to minimize the problem and lessen the impact. Granted, there are many solutions available to solving maintenance problems. But a diligent Board, who retains a diligent Engineer, can make their decision based upon catagorized options. These options are generally broken out into: must do (life and safety), should do (best for long term effectiveness) and if ‘Money Is No Object’.

Facade Defects

We were retained by the property owners of a Riverdale CO-OP to determine the cause and recommend solutions for water infiltration problems. After reviewing a survey of the residents problems we performed an in depth review of the facade. Our review consisted of complete field measurements and probes at typical locations.

Seized Relieving Angles

The building is a masonry, cavity wall structure, 18 stories in height. At each floor, above the windows, there exists a steel angle, bolted to the building’s concrete frame. Each steel angle is designed to carry the masonry dead load for (1) story of height. Beneath each angle, we discovered that the required gap, or soft joint, was nonexistent. The lack of a soft joint, at this location, imposes massive stress on the masonry facade. The masonry becomes ‘muscle bound’ and unable to grow, as masonry naturally does, due to moisture absorbtion. Furthermore, past repairs failed to identify these areas as required soft joints, and filled the void with mortar. Consequently, the masonry, unable to move, became buldged at every floor line and has started to creep off of the supporting angle.

Lack of Vertical Joints

Since masonry undergoes a volume change due to moisture absorbtion, (this volume change is not only in the up/down direction, but also in the right/left direction), vertical joints are required to relieve the built up stresses. This structure suffers from a lack of joints in the vertical direction which contributed to the cracking of masonry at the building’s corners. Another flaw discovered, was that the horizontal relieving angles, (for some reason) stop short of returning around the building’s corners by about three feet. This created a situation whereby 18 stories of masonry had no relief at all.

Brittle Flashing

During our probe we reviewed the existing flashing condition. What we found was a brittle sheet flashing that had been tornby the slab edge and penetrated by the attachment bolts for the relieving angles. Our repair involved the calculation of expansion for the masonry, the location of vertical relief joints and the rehabilitation of the horizontal relieving angles. Proper flashing and stress relief in the facade didn’t come a moment to soon with this building, since it suffered from design flaws as well as poor maintenance.

Moisture Control

Masonry removal and the placement of waterproofing within the cavity on a project in Stamford, CT

The photograph below shows masonry panels that have been removed and the placement of a waterproofing membrane over the backup, which in this case is dens-glass board on metal studs.  The green material is a self adhered sheet membrane produced by Grace that is easily applied, easily shaped and will collect the interstitial water from within the cavity and release the water at the supporting shelf angles.

facade 25F

Upper West Side, Manhattan (Mold & Mildew)

I recently assisted (2) Co-ops in the identification and removal of moisture problems thought to be caused by infiltration from the exterior. After performing numerous exterior waterproofing repairs to no avail, the Owners pleaded with us to investigate the reoccurring moisture and associated mold. Not being a mold expert, but also not afraid to back away from a fight, I did a little research.

The total tonnage of mold and condensation information in the form of research and case studies came as a complete surprise to me. After performing site visits, asking the right questions and sifting through the technical data available, I designed solutions suitable for both projects.

Since mold can only exist at a relative humidity of > 70%, (35% is desirable during the heating season at an indoor temperature of 70° F) it was my preliminary opinion that there existed a ventilation problem with the affected units. A ventilation problem, which is a rather broadstroke term, can be further broken down into constituent parts: i.e. inadequate air exchange, infiltration, exfiltration and source control. Interstitial (within wall) moisture problems are more common on North and East facing walls because of the colder temperatures on the North walls and the tendency for prevailing winds to charge the East facing cavities with indoor air by negative pressure). Mold growth can be controlled by preventing the interior surfaces of exterior walls from becoming too cold and by limiting interior moisture levels.

The interior humidity level in many of the affected units had increased, since the number of occupants in the apartments had increased. Each adult person transpires moisture during the day on the order of 3 pints each. It was safe to assume that interior water usage through bathing, washing dishes, etc. had also increased due to the number of occupants.

Since the temperature of exterior surface of the interior walls suffering from the mold problem had to be raised in order to correct the problem, we had to:

  • Completely insulate the North and East walls.
  • Seal all penetrations (outlets) and provide gasketted outlet covers.
  • Provide outward drying of the exterior (North/East) walls by installing a taped and sealed vapor barrier on the framing prior to installing the sheetrock.

To lower the humidity level within the unit, we recommended that a ducted, mechanical vent be installed in the bathrooms. These vents will probably only be needed during the heating season, since the bathrooms have a window that can be opened during warmer weather.

  • The installation of additional venting alone, would not be adequate to rectify the mold problems. The tendency of prevailing winds to charge the East facing cavities with indoor air (by negative pressure) cannot be accurately predicted or measured, therefore the venting would have to be sized for the worst case (or a reasonable percentage thereof) and could not be guaranteed effective.
  • Condensation, (and subsequent mold), occurs when cold air comes in contact with warm air. The temperature of the surface of the exterior wall must be at or higher than the dew point of the apartment at a given relative humidity to prevent condensation. The solution for the mold problem, is to raise the temperature of the cold side of the wall by installing insulation and eliminating thermal bridges (i.e.metal studs, electrical boxes, etc.)

Long term incidence of mold and mildew, due to high indoor relative humidities, is very important since the medical profession has recently linked biological contaminants to respiratory infections and allergic reactions. If the range of indoor humidity can be lowered to 30%-50%, the growth of biologicals such as dust mites and associated health problems – such as asthma, can be avoided.

IRMA waterproofing for a courtyard over a parking structure

The waterproofing being applied is a SBS torch down system over a concrete deck. AKA IRMA (inverted roof membrane application). This type of system is applied directly to the concrete deck. A drainage mat is applied over the membrane. On top of the drainage mat insulation is placed, then the walking surface composed of pavers is set.  The right photograph shows the the inside of one of the several planters.  All of the topsoil and vegetation was removed.  The area was cleaned and Alsan RS flashing was used for a watertight condition.  Copper weeps were also installed around the planter perimeter.

IRMA membrane Planter WP

Capillary Suction

Manhattan Facade (Capillary Suction)

After infiltration repairs to the facade of a 19 story Manhattan residential building proved ineffective, I performed an inspection from a rig to examine the problem. The facade is white, glazed masonry, veneer (cavity wall) with block back-up. The flashing system was original and composed of PVC. The isolated infiltration that was occurring at the window heads was examined closely and was field tested to determine the source. We saturated the masonry above several windows with water and created a sheeting of water down the facade. We observed the sheeting water curling under the brick at the window openings. The water then made contact with the toe of the steel lintel. At this location, the water was sucked under the original PVC flashing membrane (which is brittle and not adhered to the steel lintel). The water then accumulated at the lintel heel (due to the back pitch of the lintel). Without an exit, the water accumulated until it ran right and left off of the lintel and into the area above the window sides.

This phenomenon is known as capillary suction . Capillary suction (in exterior walls) can be defined as a suction force between small passages of less than 1/8″. When you couple this force with the stack effect in the cavity wall, the difference in relative humidity between inside the cavity and the exterior causes the unequal pressures to want to reach equilibrium. Moisture will be drawn into this void until a state of equilibrium is reached. Since the offending lintels are back pitched, the water accumulates at the lintel heel, prolonging the equilibrium process and the suction at the lintel toe continues unabated. The back pitched lintel (although slight) is a result of facade compression. Facade compression is usually accompanied by spalled masonry (which we do not have in this case), so the lintel condition is difficult to detect without an invasive probe.

The Solution
To prevent capillary suction one must either have equal pressures inside the cavity and outside (which isn’t practical), or and more practical, eliminate the 1/8″ void beneath the flashing and reshim the steel lintel to eliminate the back pitch. This involves masonry removal, lintel detachment, insertion of shims (or a new lintel), installation of flashing adhered to the lintel with end dams, and reinstallation of the masonry.

Parking Structures

Post tensioned garage strands

These photos are of broken post tensioned strands and their splicing.  PT strands provide compression forces within parking garage slabs allowing for long spans and minimal reinforcement.  Unfortunately, corrosion can occur and cause these stands to break.

Under extreme tension (approx 30,000  psi) when these strands break, the slack causes a concrete spall.  These strands are accessed, spliced and re-tensioned as needed as repairs.  The use of a topping membrane will reduce the infiltration, corrosion and maintenance with this garage system.

Photos - 2160 Photos - 0495 post tension OLYMPUS DIGITAL CAMERA

Expansion to an existing Precast Garage

In New Jersey, Cowley Engineering designed an expansion to the existing precast parking structure for the county municipal building and detention center. Using Castellated members and custom support brackets, the existing parking structure was raised an additional 2 levels and expanded into the hillside.

suss 2 suss

Continuum Health services in NYC

Below is a photograph of the concrete removals and associated shoring required for the rehabilitation of a parking structure on West 59th street, in Manhattan.  The floor areas were sounded for delaminated concrete and marked out with spray paint. The areas are then saw cut and shored prior to commencing the removal of the delaminated areas. Protection, shoring and dust control as well as accommodating the continued use in other portions of the garage contribute to the complexity of these repairs.  This structure was a combination concrete joists with one way slabs at the perimeter.

515 W 59

Column, beam and overhead repairs of a parking structure below a residential condominium complex in Greenwich, Connecticut.

The repairs required in this garage were relatively minor and involved removals of spalled sections due to infiltration from above and high moisture levels within the garage structure.  Although unsightly, the structure was not comprised due to the light load and minor decay.  Some repairs of the corner bars of the columns extended to the pier tops below the asphalt layer.

.ogg garage

Carbon fiber biscuits for precast planks

Precast parking garages are replete with joints between the precast planks.  When assembled, the edges of the precast planks are welded intermittently by dropping a metal rod between steel embeds that are factory cast into the precast plank edges.  Over time, bouncing and corrosion cause these welds to break.  The best solution to maintain alignment of these plank edges is to epoxy insert carbon fiber ‘biscuits’ at 45° angles along the edges, that bridge the two plank edges.  The saw cuts of the biscuits is shown in the photo below.

CF Biscuits

Garage slab and beam repairs in a mid town residential high rise.

In the two photographs below, you can see the partial and complete removal of decayed concrete due to lack of maintenance and lack of a traffic bearing water proofing system in the drive lanes and parking areas.  The one way slabs and beams were shored was necessary, the reinforcement was replaced as needed and the area was re-cast.

300 E 47 garage 301 e 47 gar2

Riverdale, NY, (Parking Structure Rehab)

project1We recently completed an extensive parking structure renovation for a Riverdale Co-op. The garage consists of 36,000 sf of parking and a 18,000 sf. roof deck. The framing system consists of 2 way concrete joists (aka waffles) supported by round concrete columns.

Our approach to the job was to complete accurate drawings depicting the conditions of the structure. We determined the areas of delaminated concrete by chain dragging the decks. A chain drag is a ‘sophisticated’ tool, much like a broom, with chains attached where the broom bristles would normally exist. By ‘sweeping’ the deck with this tool, the difference in sound emitted between solid concrete and delaminated concrete indicates a void. We mapped out these voids on our plan and generated BID documents indicating quantities for full depth, moderate depth and minor repairs. We also estimated the lineal footage of overhead rib repair, roofing material, column patches, window replacement, masonry replacement, air handler replacement, painting, security cameras, etc. for a complete job.

The job was awarded to the lowest qualified bidder. Owner modifications and concrete area overages brought the final job total over the estimate by about 5%.

During the planning, the Owners opted for a traffic membrane to be applied on the drive and parking areas. This membrane, applied in (2) layers in the parking areas and in (3) layers in the drive lane and turning lane areas, is a composite system consisting of an elastomeric waterproofing layer and a sand broadcast-into-epoxy wearing surface. This type of membrane is a must for parking structures located in the North East and was applied to the drive surface of the newly cast concrete deck. Not only is there the obvious waterproofing benefits, the membrane also has excellent sound absorption abilities, removing the screeching tire effect and deadening the normal echoes typical to enclosed concrete parking structures.

The work was phased so the garage could be used during the repairs. Only during the repairs at the entries and during the membrane application, did the garage have to be closed completely. The Owners utilized a parking valet service during this time and made temporary accomodations with a local synagogue for the time when the garage had to be completely closed.

The garage work was completed in less than 8 weeks, while the exterior work, roofing and masonry required an additional 4 weeks.

Structural

Catch -All and work platform above the all glass Apple Store

Prior to repairing the southwall of my client building, Cowley Engineering had to come up with a protection scheme for the Apple Store on the Upper West side.  Eric designed wall brackets cantilevered from his client’s building capable of supporting and landing swing stage scaffolding.  The platform also provided support for the jib and netting system that extended 25 feet.  Cowley was given this authorization contingent upon NOTHING touching Apple’s property.

IMG_3396

Column Repair on West 41st Street

This property is a lovely, prewar structure that was in need of TLC.  Past bankruptcy issues contributed to maintenance deferment for many years.  Vertical cracks on both sides of the corners were present for the full height (28 stories) of the structure causing stability issues of the fractured masonry that required pedestrian protection.  Finally,  a heads up bank receiver and an experienced property manager hired Cowley Engineering to make corrections and stabilize the conditions.  The photograph below shows one of the corner columns exposed, repaired and ready for waterproofing and re-masonry.

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Owner’s representative for west village development

In 2013, we performed Owner’s representative services during the development of a residential tower at the corner of Charles and Washington streets in the west village.  It was our job to monitor the progress of the structure and its effects on the neighboring properties.  The photos below show that the property to the east is supported by piles and does not have a foundation bearing on grade as was suspected.

no underpinning 2no underpinning

Horse riding arenas with metal plated wood trusses.

We have provided structural design services on wood framed riding arenas in Westchester County, Dutchess County and Saratoga County.  These long span structures with relatively low slopes where designed for the code required snow loads in the various counties.  Below are 3 of the projects.

horse arena BHF2 arena 2

Forensic

Rite Aid vs Red Apple Development (Construction and design defects)

This matter was concerned with alleged design and construction defects with a structure in Manhattan in a build to lease situation.

Condominium #50 vs Bridge Street Development (Construction defects)

This matter was concerned with alleged design and construction defects in the conversion of a Brooklyn building from warehouse to condominiums.

Arianna Condominium vs Tiffany Development (Construction defects)

This matter was concerned with alleged design and construction defects in the conversion of a Brooklyn building from warehouse to condominiums.

Fabio vs 21St Associates, LLC (Damage during foundation operations)

This matter was concerned with alleged damage to a neighboring structure during the development and construction of a new residential high rise in Queens.

‘Plaintiff’s family’ vs Metro Sign (Wall collapse resulting in fatality)

This matter was concerned with alleged damage to a neighboring structure during removal of a billboard that resulted the partial collapse of a lot line wall that resulted in a fatality.

237 West 123rd Street LLC vs A. Aleem Construction, Inc.

This matter was concerned with alleged design and construction defects that lead to damage to a neighboring structure.

Madison Towers vs Tower Construction Corp.

This matter was concerned with an alleged construction defect that lead to the collapse of a pedestrian access stair to a parking deck.